The Windows Communication Foundation and other distributed system platforms have a decoding process, in which an external representation (or format) of a message is converted into some internal representation (or format). The external representation of the message is more suited towards the delivery system to get the message into and out of the system, whereas the internal representation can be processed by the system itself. An example of a common internal representation is, for example, eXtensible Markup Language (XML) or Infoset data. Likewise, the system has an encoding process in which an internal representation of a message is converted into some external representation for transport.
Traditionally, the choice of external message formats is static. All messages originating from a certain endpoint are encoded into the same format, and all messages accepted by a certain endpoint are expected to be in a certain format. There is conventionally some level of format auto-detection capabilities for incoming messages. For example, some conventional systems can automatically detect whether an incoming message is using UTF8 or UTF16 character encoding or whether the message is plain XML or is it an MTOM (Message Transmission Optimization Mechanism) message. However, these format differences are not significant enough that different processing is needed further up in the stack. Accordingly, once a basic transform is applied during decoding, no other action need be taken in order to accept the message.